In fact, I did get Ubuntu working the other night but it was too late to post any more updates. What I had to do was use the desktop version of the distro as opposed to the server version (still 64 bit though). I’m writing this on the new machine.
Before I did that I used the menu system to save the install logs and opened a shell to have a look. It seems like Ubuntu itself runs fine and the installer is at fault. Perhaps I need a more up-to-date version of the Universal USB Installer. The error messages are misleading as I believe there are just files missing from the USB drive (mounted on /cdrom). “There was a problem reading from the CD-ROM…” Not really but I guess the installer assumes it has all the files. Still, misleading error messages are one of the banes of IT.
Now to download some hypervisors and other O/Ss.
P.S. Ubuntu likes to spread itself about on the disk if you choose a fully automated install. I wanted the minimum, a / filesystem and some swap and I created a couple of small partitions for that but it still went and used the 900G of space for swap so I had to explicitly tell it what to use.